The 1965–66 Regional Championship was the 24th season of the Liga IV, the fourth tier of the Romanian football league system.
[2][3] Metalul Oțelu Roșu won the Banat Regional Championship and qualify to promotion play-off in Divizia C. The matches were played on 5 and 12 June 1966.
Gloria Ioșia won the Crișana Regional Championship and qualify to promotion play-off in Divizia C. The matches were played on 12 and 19 June 1966.
Confecția Odorheiu Secuiesc won the Mureș Regional Championship and qualify to promotion play-off in Divizia C. The matches were played on 12 and 19 June 1966.
Autorapid Craiova won the Oltenia Regional Championship and qualify to promotion play-off in Divizia C. The matches were played on 19, 26 and 29 June 1966.